Category Archives: Research

Blake Klocke, a student at George Mason University is studying where frogs go once we release them, how long it takes them to contract the chytrid fungus, if there are any effects of releasing chytrid susceptible frogs on the existing frog community & what other non chytrid fungus sources of mortality might affect reintroduction work.

In addition to our primary project partners the Houston Zoo, Zoo New England and the Cheyenne Mountain zoo we thanks the National Geographic Society, Mohammed Bin Zayed Species Conservation Fund, and the Smithsonian Women’s Committee for their support of these release trials.

Many infectious diseases can fade away after initial outbreaks. Bubonic plague, cholera, and influenza are examples from recent human history. The same phenomenon occurs for wildlife diseases as well. How does this happen? One popular explanation is that the pathogen evolves to become less deadly, so that it doesn’t completely wipe out its hosts, ensuring pathogen survival. While this scenario does sometimes play out, we know that there are other reasons why the severity of diseases can change over time.

Cori Richards and Jamie Voyles

For amphibians, we’ve known about a highly lethal disease called “chytridiomycosis” since the 1990s. This disease was especially devastating in Central America, where it may have wiped out entire species. In this study, we made the exciting discovery that some amphibian species – frogs that were thought to be extinct – are persisting, and even recovering, after lethal disease outbreaks. We wanted to understand how it was happening. Was it a change in the pathogen, the frogs, or both?

To answer these questions, we did two things. To begin with, we surveyed frogs in Panama before and after the disease outbreak. In addition, we collected samples of the pathogen at multiple time points: during initial outbreaks and ~10 years later. We found that nearly a decade after the outbreak, the pathogen was just as deadly. However, the frogs are surviving and have better defenses against it. Panama’s frogs are fighting back! Understanding how amphibian communities are recovering after this disease outbreak is important multiple reasons. First, resolving how this works will help us develop more informed conservation strategies to protect amphibians from disease-induced extinctions. Second, clarifying how disease outbreaks subside will help us predict, and respond to, other emerging pathogens in plants, wildlife, and in humans. These goals are increasingly important in a time when rapid globalization has increased the introduction of pathogens to naïve host populations.

Atelopus varius is one species that appears to have evolved antifungal skin secretions

Once common along highland streams from western Costa Rica to western Panama, the variable harlequin frog is endangered throughout its range, decimated by a disease caused by the amphibian chytrid fungus. On Jan. 17, Smithsonian researchers released approximately 500 frogs at Cobre Panama concession site in Panama’s Colon province as a first step toward a potential full-scale reintroduction of this species. This release trial is included in Cobre Panama’s biodiversity conservation plan as an important part of their environmental commitments.

Composite image showing variation in coloration within this population of frogs

The variable harlequin frog, Atelopus varius, takes its name from the variety of neon colors—green, yellow, orange or pink—juxtaposed with black on its skin. In order to monitor the released frogs over time, 30 are wearing miniature radio transmitters. The scientific team also gave each frog an elastomer toe marking that glows under UV light to mark individuals as part of a population monitoring study.

“Before we reintroduce frogs into remote areas, we need to learn how they fare in the wild and what we need to do to increase their chances of survival in places where we can monitor them closely,” said Brian Gratwicke, international coordinator of the Panama Amphibian Rescue and Conservation project (PARC) at the Smithsonian Conservation Biology Institute. “Release trials may or may not succeed but the lessons we learn will help us to understand the challenges faced by a frog as it transitions from captivity into the wild.”

Heidi Ross and her team at our facilities in the Nispero Zoo successfully bred and reared these animals for the release trial

Variable harlequin frogs are especially sensitive to the amphibian chytrid fungus, which has pushed frog species to the brink of extinction in Central America. PARC brought a number of individuals into the breeding center between 2013 and 2016 as chytrid continued to impact wild populations.

The field team all assembled with frogs ready for the release trial

“The variable harlequin frog is one of the closest relatives of Atelopus zeteki, Panama’s iconic golden frog, another target species in our captive breeding program,” said Roberto Ibañez, PARC project director at the Smithsonian Tropical Research Institute in Panama. “We’ll be monitoring the surrounding amphibian community and the climate at this site, and comparing this to the amphibian community at another, control site. This kind of intensive monitoring will help us to understand disease dynamics in relation to the release trials”

One of our Atelopus varius wearing a mini radio-transmitter

PARC hopes to secure the future for this and other endangered amphibians by reintroducing animals bred in captivity according to an action plan developed with Panama’s Ministry of the Environment and the International Union for the Conservation of Nature (IUCN) and other stakeholders. “It took us several years to learn how to successfully breed these frogs in captivity,” said Ibañez. “As the number of individuals we have continues to increase, it provides new research opportunities to understand factors influencing survival that will ultimately inform long-term reintroduction strategies.”

The PARC project thanks Cobre Panama, National Geographic Society, Mohammed bin Zayed Species Conservation Fund and The WoodTiger Fund for their generous support.

SCBI plays a leading role in the Smithsonian’s global efforts to save wildlife species from extinction and train future generations of conservationists. SCBI spearheads research programs at its headquarters in Front Royal, Va., the Smithsonian’s National Zoo in Washington, D.C., and at field research stations and training sites worldwide. SCBI scientists tackle some of today’s most complex conservation challenges by applying and sharing what they learn about animal behavior and reproduction, ecology, genetics, migration and conservation sustainability.

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The Institute furthers the understanding of tropical biodiversity and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.

Scientists at the Smithsonian Institution and partners have published a paper that optimizes sperm collection protocols from the critically endangered Panamanian Golden Frog Atelopus zeteki. It also improves our understanding of reproduction in endangered harlequin frogs. The research, to be published published 15 March 2017, in Theriogenology, was conducted by Dr. Gina DellaTogna, a Panamanian biologist who studied this charismatic animal at the National Zoological Park in Washington DC. The study characterizes the dose-response patterns for several artificial hormone treatments and describes the sperm morphology for the first time in this species.

Atelopus zeteki spermatazoan

“This study is important, because it contributes towards the basic understanding of reproduction of a highly endangered group of frogs in Latin America,” said DellaTogna, who performed the experiments for her PhD at the University of Maryland. “This study has already helped us to solve critical reproduction problems in captive Atelopus collections in Panama and allowed us to repeatedly collect high-quality sperm samples for genome resource banking at any time of the year, without harming the frogs.”

“Basic reproductive research is something that has yielded huge conservation dividends for the successful care and management of other endangered species like Pandas and Black Footed Ferrets,” said Pierre Comizzoli, a co-author of the paper and reproduction specialist at the National Zoo. “Gina’s research opens the door to develop methods like sperm freezing and storage to preserve the long term genetic integrity and diversity in small populations.”
The research is particularly relevant to current amphibian conservation efforts in Panama where the Panama Amphibian Rescue and Conservation Project has captive-breeding colonies of five species of Atelopus that are threatened with extinction from the deadly fungal disease chytridiomycosis.

Roberto Ibáñez, and Gina DellaTogna working on hormonal stimulation of frogs at the Panama Amphibian Rescue and Conservation Project

“Successful reproduction is key to any captive assurance program,” said Roberto Ibáñez, the director of the Panama Amphibian Rescue and Conservation project at the Smithsonian Tropical Research Institute in Panama. “Gina has already begun applying what she has learned to successfully help us to produce offspring from four other endangered harlequin frog species. I hope that she will eventually extend it to species with different modes of reproduction that are also difficult to breed”.

The research was made possible with assistance from the Maryland Zoo in Baltimore who manage the Golden Frog Species Survival Plan. Funding was provided from the Panamanian Government’s Secretaría Nacional de Ciencia y Tecnología (SENACYT), The WoodTiger Fund, the Smithsonian Endowment for Science and the University of Ottawa Research Chairs Program.